Buggy code:
public class FunctionKeyApp { private final Properties settings ; private final Properties settingTOA ; private final Properties settingCS ; private final char FIELD_DELIMITER ; private final String lineSeperator ; private List < String > lineList ; public FunctionKeyApp ( Properties settings , char delimiter , String lineSeperator , Properties settingTOA , Properties settingCS ) { } public void fn_setTheLineList ( String line ) { } public List < String > fn_newTheLineList ( String line ) { } public String fn_onlyInsertOriginal ( String configSingleValue ) { } public String fn_acCompanyCode ( String configSingleValue , String uploadCompanyCode ) { } public String fn_insertOther ( String configSingleValue ) { } public String fn_clearingSuspense ( String configSingleValue , String uploadCompanyCode ) { } public String fn_TOAJudge ( String configSingleValue , String uploadCompanyCode ) { } public String fn_negateValue ( String configSingleValue ) { } public String fn_combine2FieldValue ( String configSingleValue ) { } public String fn_onlyTOAInsert ( String configSingleValue , String uploadCompanyCode ) { } String Limit_formatLine_Parent = "" ; String Limit_formatLine_Child = "" ; Set < String > ListMap = new HashSet < String > ( ) ; HashMap < String , String > mapValue = new HashMap < String , String > ( ) ; public String fn_getLimitZero ( ) { } public String fn_limitZero ( String configSingleValue ) { } StringBuilder customer = new StringBuilder ( ) ; public String fn_getEmailFormat ( ) { } public String fn_CustomerFormat ( String configSingleValue ) { } int ix = 1 ; StringBuilder group = new StringBuilder ( ) ; public String fn_getGroupFormat ( ) { } public String fn_GroupFormat ( String configSingleValue ) { String [ ] putArray = getIndexOrValue ( configSingleValue , null ) . split ( "," ) ; String getContrastValue = "" ; String [ ] subSeparateArray ; String newValue = "" ; for ( int pair = 1 ; pair < ( putArray . length ) ; pair += 2 ) { int amountCut = lineList . get ( Integer . parseInt ( putArray [ pair ] . trim ( ) ) ) . split ( putArray [ 0 ] ) . length ; subSeparateArray = getIndexOrValue ( ( configSingleValue + ( putArray [ ( pair + 1 ) ] . trim ( ) ) ) , null ) . split ( "," ) ; getContrastValue = lineList . get ( Integer . parseInt ( putArray [ ( pair + 1 ) ] . trim ( ) ) ) ; if ( ( ( subSeparateArray [ 0 ] ) != "" ) && ( ( getContrastValue . length ( ) ) > ( Integer . parseInt ( subSeparateArray [ 1 ] . trim ( ) ) ) ) ) { getContrastValue = handleMultiAndSubField ( getContrastValue , subSeparateArray [ 0 ] , Integer . parseInt ( subSeparateArray [ 1 ] . trim ( ) ) ) ; } newValue += getContrastValue ; <START_BUG> if ( ( amountCut > 1 ) && ( getContrastValue != "" ) ) { <END_BUG> for ( int plus = 1 ; plus < amountCut ; plus ++ ) { newValue += putArray [ 0 ] ; newValue += getContrastValue ; } } lineList . set ( Integer . parseInt ( putArray [ ( pair + 1 ) ] . trim ( ) ) , newValue ) ; newValue = "" ; getContrastValue = "" ; } for ( int i = 0 ; i < ( lineList . size ( ) ) ; i ++ ) { if ( i != 0 ) { group . append ( FIELD_DELIMITER ) ; } group . append ( lineList . get ( i ) ) ; } group . append ( lineSeperator ) ; return "" ; } public static String areplace ( String str , String patten , String replacement , int pos ) { } private String getTOAString ( String CompanyCode , String uploadCompanyCode ) { } private String getIndexOrValue ( String configSingleValue , List < String > lineList ) { } private BigDecimal getBigDecimal ( String moneyInput ) { } private BigDecimal getBigDecimalNoPoint ( String moneyInput ) { } private List < String > lineSeparete ( String line ) { } private String handleMultiAndSubField ( String currentField , String delimiter , int cutLengthInt ) { } }

Fix:
if ( ( amountCut > 1 ) && ( ! ( getContrastValue . equals ( "" ) ) ) ) {